The present invention relates generally to novel herbicidal compounds and methods for their use in controlling unwanted plant species in agriculture. In particular, the present invention pertains to cycloimido-substituted benzofused heterocyclic herbicides, and more particularly it pertains to herbicides in which the benzofused heterocycle is a benzofuran, benzimidazole, a 2,3-dihydrobenzimidazole, or indole having a cycloimido moiety which is a 1 -substituted-6-trifluoromethyl-2,4-pyrimidinedione-3-yl, a 1-substituted-6-trifluoromethyl-1,3,5-triazine-2,4-dion-1-yl, a 3,4,5,6-tetrahydrophthalimid-1-yl, a 4-difluoromethyl-4,5-dihydro-3-methyl-1,2,4-triazol-5(1H)-on-1-yl, a 5,6,7,8-tetrahydro-1H,3H-[1,3,4]thiadiazolo[3,5-a]pyridazineimin-1-yl, or a 1,6,8-triazabicyclo[4.3.0]-nonane-7,9-dion-8-yl ring.
It has now been found that certain cycloimido-substituted benzofused heterocyclic compounds are useful as pre-emergent and postemergent herbicides. These novel compounds are represented by formula I: 
where J is a 1-substituted-6-trifluoromethyl-2,4-pyrimidinedione-3-yl, a 1-substituted-6-trifluoromethyl-1,3,5-triazine-2,4-dion-1-yl, a 3,4,5,6-tetrahydrophthalimid-1-yl, a 4-difluoromethyl-4,5-dihydro-3-methyl-1,2,4-triazol-5(1H)-on-1-yl, a 5,6,7,8-tetrahydro-1H,3H-[1,3,4]thiadiazolo[3,5-a]pyridazineimin-1-yl, or a 1,6,8-triazabicyclo[4.3.0]-nonane-7,9-dion-8-yl ring attached at the 7 position of a benzofuran, benzoxazole, 2,3-dihydrobenzimidazole, indole or benzimidazole, and X is selected from hydrogen, halogen, cyano, nitro, alkyl, haloalkyl, and amino. Preferred R groups are optionally substituted alkyl groups.
Certain cycloimido-substituted benzofused heterocyclic compounds have now been found to be useful as pre- and postemergent herbicides. These compounds are represented by formula I: 
where
(1) A is nitrogen double-bonded to position 2 and B is oxygen;
(2) A is oxygen and B is CRxe2x80x2 double bonded to position 2;
(3) A is NH and B is nitrogen double-bonded to position 2;
(4) A is nitrogen double bonded to position 2 and B is NR2;
(5) A is CH double bonded to position 2 and B is NR2;
(6) A is NH and B is CRxe2x80x2 double bonded to position 2; or
(7) A and B are NH
R is hydrogen, hydroxy, mercapto, straight or branched chain lower alkyl, cycloalkyl, alkoxy, aryl, heteroaryl, alkenyl, haloalkyl, hydroxyalkyl, haloaryl, alkoxyaryl, arylalkyl, aryloxyalkyl, haloarylalkyl, alkylthio, heterocyclyl, alkoxyalkyl, alkoxylalkyloxyalkyl, alkylcarbonyloxyalkyl, arylcarbonyloxyalkyl, aminocarbonyloxyalkyl, aminoalkyl, cyanoalkyl, aminoalkenyl, carboxy, carboxyalkyl, alkylcarboxy, alkylcarboxyalkyl, formyl, aminocarbonyl, amino, oxygen, cyano, nitro, alkylsulfonyl, aminosulfonyl, alkylsulfonylamino, alkoxycarbonyloxyalkyl, alkylcarboxylalkoxy, alkoxycarbonylamino, alkoxycarbonylalkylaminoalkyl, aryliminoalkyl, (aryl)(alkoxy)alkyl, (aryl)(alkylcarbonyloxy)alkyl, arylalkoxyalkyl, cyanoalkylthio, alkynylalkylthio, arylalkylthio, cyanothio, cyanothioalkyl, alkoxycarbonylalkylthio, aminocarbonylalkylthio, alkenylalkylthio, haloalkylalkynylalkylthio, aminocarbonyloxyalkyl, arylalkylcarbonylaminoalkyl, (hydroxy)(aryl)alkyl, alkylcarbonylaminoalkyl, alkylsulfonylaminoalkyl, aminocarbonylalkyl, alkoxycarbonyl, and alkenyloxy, where the amino group may be substituted with one or two substituents independently selected from alkyl, hydroxy, alkoxy, carboxy, aryl, alkylsufonyl, or haloalkylsulfonyl;
R1 is hydrogen, lower alkyl, or haloalkyl;
R2 is hydrogen, alkyl, haloalkyl, CO2(alkyl), CH2CO2(alkyl), CH2CONH-alkyl, CH2CON(alkyl)2, CH2CO2H, CH2OCH3, SO2(alkyl), CH2CHxe2x95x90CH2, CH2Cxe2x89xa1CH.
X is selected from hydrogen, F, Cl, Br, alkyl, haloalkyl, CN, NO2, and NH2;
n is 0-3;
J is selected from 
and
R3is selected from hydrogen, alkyl, haloalkyl, CH2CN, CH2CHxe2x95x90CH2, CH2Cxe2x89xa1CH, CH2CO2(alkyl), CH2OCH3, and NH2.
Preferred compounds are those of formula I where R is CH3, CH2CH3, C(CH3)2OH, CH2CH2OH, CH(CH3)2, t-butyl, CF3, CH(F)CH3, CF2CF3, C(CH3)2OCOCH3, C(CH3)2NHSO2CH3, CH2CH2CH2Cxe2x89xa1N CH2CH2CO2CH3, and CON(CH3)2; X is a chlorine, bromine or fluorine substituted in one or both of positions 4 and 6; J is 
and R3 is CH3 or NH2.
One aspect of the present invention relates to compounds of formula I in which A is nitrogen double-bonded to position 2 and B is oxygen, and R, R3, J, X and n are as described above.
Another aspect of the present invention relates to compounds of formula I in which A is oxygen and B is CR1 double bonded to position 2, and R, R1, R3, J, X and n are as described above.
Another aspect of the present invention relates to compounds of formula I in which A is NH and B is nitrogen double-bonded to position 2, and R, J, X and n are as described above.
Another aspect of the present invention relates to compounds of formula I in which A is nitrogen double bonded to position 2 and B is NR2,and R, R2, R3, J, X and n are as described above.
Another aspect of the present invention relates to compounds of formula I in which A is CH double bonded to position 2 and B is NR2, and R, R2, R3, J, X and n are as described above.
Another aspect of the present invention relates to compounds of formula I in which A is NH and B is CR1 double bonded to position 2, and R, R1, R3, J, X and n are as described above.
Another aspect of the present invention relates to compounds of formula I in which A and B are NH and R, R1, R3, J, X and n are as described above.
Another aspect of the present invention relates to compounds of formula I where J is not 
when: A is oxygen and B is CR1 double bonded to position 2; A is CH double bonded to position 2 and B is NR2; or A is NH and B is CR1 double bonded to position 2; and R, R1, R3, X, and n are as described above.
As shown in the specification a wide range of substituents is described for position B in compounds of formula I whereas position A is generally unsubstituted. It was found that some herbicidal activity is retained when a methyl substituent is placed at position A, but that substitution at that position generally causes a sharp decrease in activity.
Certain intermediates of the present invention are novel. These include compounds of formula II: 
where Y is NO2, NH2, or xe2x80x94NHNxe2x95x90C(CH3)R; Z is hydrogen, F, NH2, or OH; and R, J, X, and n are as described above; with the proviso that when Y is xe2x80x94NHNxe2x95x90C(CH3)R, Z is hydrogen.
As used in this specification and unless otherwise indicated, the terms xe2x80x9calkyl,xe2x80x9d xe2x80x9calkenyl,xe2x80x9d xe2x80x9calkynyl,xe2x80x9d xe2x80x9ch aloalkyl,xe2x80x9d and xe2x80x9calkoxyxe2x80x9d used alone or as part of a larger moiety, includes straight or branched carbon chains of 1 to 6 carbon atoms. xe2x80x9cHalogenxe2x80x9d refers to fluorine, bromine or chlorine. xe2x80x9cTHFxe2x80x9d means tetrahydrofuran, xe2x80x9cDMFxe2x80x9d means N,N-dimethylformamide, and xe2x80x9cDBUxe2x80x9d means 1,8-diazabicyclo[5.4.0]undec-7-ene. When xe2x80x9cnxe2x80x9d in xe2x80x9cX(n)xe2x80x9d is 2 or 3, the substituents X may be the same or different from one another. 
a) 70% HNO3/ H2SO4, 0-5xc2x0 C.; (b) NaOSi(CH3)3, MeOH, dioxane; (c) Fe, EtOH, acetic acid, HCl, heat; (d) CF3C(NH2)xe2x95x90CO2CH2CH5, NaOSi(CH3)3, DBU, DMF; (e) CH3I, K2CO3, DMF, 60-80xc2x0 C.; (f) HCl, NaNO2, NaI, H2O; (g) BBr3, CH2Cl2; (h) HCxe2x89xa1CR, Pd(Ph3P)2Cl2, Cul, triethylamine.
Benzofurans of formula I, where A is oxygen and B is CH double bonded to position 2, may be generally prepared as shown in Scheme 1. Starting with an appropriately substituted fluoroaniline derivative 1, nitration provides intermediate 2. Displacement of the fluorine of 2 with a methoxy group as shown in step b, followed by reduction of the nitro group as shown in step c provide the methoxyaniline 3. The methoxyaniline 3 is a versatile intermediate from which a number of compounds of the present invention can be made by attachment of various J groups. For example, a uracil ring may be appended as shown in step d to give intermediate 4a. At this point, R3 substituents other than H may be introduced, as shown for example in step e to provide 4b where R3 is methyl. Using diazotization conditions (step f) 4b is converted to the iodoanisole 5 which is then deprotected to give the iodophenol 6. Palladium-catalyzed acetylenic coupling and ring closure as shown in step h give benzofurans 7 of the present invention. To obtain benzofurans of formula I where the J group is other than uracil, approaches analogous to that outlined in Scheme 1 may be followed. Such approaches based on Scheme 1 would be known to one skilled in the art. 
a) 70% HNO3/H2SO4, 0-5xc2x0 C.; (b) Fe, aqueous acetic acid, 50xc2x0 C.; (c) RCOCl, pyridinium p-toluenesulfonate, triethylamine, xylene; (d) 1,1-carbonylimidazole, THF; (e) Rxe2x80x2-halide, Ag2O, CH2Cl2 (to give 11 where Rxe2x95x90Rxe2x80x2O).
Benzoxazoles of formula I, where A is nitrogen double bonded to position 2 and B is oxygen, may be prepared as shown in Scheme 2 above. Starting with a phenol such as intermediate 8 nitration under standard conditions gives the nitrophenol 9. Certain of the benzoxazoles 11 of the present invention may be obtained by reduction of 9 to the aniline 10 followed by treatment with an acid halide (such as shown in step c). Alternatively, other benzoxazoles 11 may be obtained by treating 10 with carbonyldiimidazole to give intermediate 12 which can be O-alkyated according to step e. The approach outlined in Scheme 2 can be adapted, in ways known to one skilled in the art, to obtain benzoxazoles of formula I where the J group is other than uracil. 
a) see steps (d) and (e) of Scheme 1; (b) 70% HNO3/H2SO4, 0-5xc2x0 C.; (c) NH4OAc, triethylamine, dioxane, heat; (d) SnCl2 H2O or Fe, NH4Cl, aqueous ethanol, heat; (e) RCO2H, heat; RCO-halide, CH2Cl2/Pyridine, then POCl3, CH2Cl2; alkoxycarbonyl isothiocyanate, HgCl2, heat (where R is xe2x80x94NHCO2alkyl); or thiophosgene, EtOAC, heat (where R is xe2x80x94SH).
Benzimidazoles of formula I, where A is NH and B is nitrogen double bonded to position 2, may be prepared as shown in Scheme 3 above. For example, intermediate 13 may be converted to the uracil 14 by the well-known chemistry previously described. Nitration of 14 followed by aminolysis of the fluorine group (steps b and c) provides the nitroaniline 15. The diamine 16 is obtained by reduction of 15 under standard conditions. Benzimidazoles 17 of the present invention are obtained by treatment of 16 with a carboxylic acid, an acid halide, an alkoxycarbonyl isothiocyanate, or thiophosgene according to step e. Other benzimidazoles 17 of the present invention are obtained by derivativization of benzimidazoles depicted in Scheme 3 using techniques known to one skilled in the art. The approach outlined in Scheme 3 can be adapted, in ways known also to one skilled in the art, to obtain benzimidazoles of formula I where the J group is other than uracil. 
Benzimidazoles of structure 17A where R3 is NH2 are prepared in a manner analogous to that depicted in Scheme 3, except the NH2 group is attached following nitration of the phenyl ring. The 1-unsubstituted uracil ring is formed as previously described in step d of Scheme 1, followed by nitration of the phenyl ring (Scheme 3, step b). The uracil ring is then aminated in the 1-position by methods known in the art by treating it with 1-aminooxysulfonyl-2,4,6-trimethylbenzene. The 1-aminouracil is then subjected to aminolysis of the phenyl fluorine (step c) followed by reduction to the diamine (step d). 
2,3-Benzimidazoles of formula I, where A and B are NH may be prepared from Intermediate 16 in Scheme 3 by heating it with an appropriately substituted acetaldehyde ethyl hemiacetal, affording compounds of Structure 17B. 
a) i. NaNO2, HCl; ii. SnCl2xe2x80x22H2O; iii. RCOCH3; (b) polyphosphoric acid, 80xc2x0 C.
Indoles of formula I, where A is CH double bonded to position 2 and B is NR1, may be prepared according to Scheme 4 above. Using a Fischer indole route the starting aniline 18 may be converted to the corresponding hydrazone 19 which in turn may be cyclized under acidic conditions such as is shown in step b. The resulting indoles 20 of the present invention may be further derivatized by alkylation of the indole ring nitrogen to indoles of formula I where R1 is other than hydrogen. The approach outlined in Scheme 4 can be adapted, in ways known to one skilled in the art, to obtain indoles of formula I where the J group is other than uracil. 
Indoles of formula I, where A is NH and B is CR1 double bonded to position 2, may be prepared by a Fischer indole synthesis analogous to that shown in Scheme 4 starting with aniline 21. Substitution at the 3 position of indoles such as 22 with R1 groups is known to one skilled in the art.